Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
  • G01N23/06—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption
  • G01N23/18—Investigating the presence of flaws defects or foreign matter
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
  • G01N23/06—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption
  • G01N23/083—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption the radiation being X-rays
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
  • G01N23/06—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption
  • G01N23/16—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption the material being a moving sheet or film

Definitions

• the present invention concerns a measuring ap ⁇ paratus, and a corresponding procedure, for measuring faults in a pipeline and for observing foreign objects occurring in a pipeline.
• the object of the invention is to eliminate the drawbacks mentioned above. Specifically, the object of the invention is to create a measuring apparatus, and a corresponding measuring procedure, by the aid of which the condition of pipelines can be monitored whenever desired, without interfering with their use in various processes, and with the aid of which faults in the pipelines can be accurately located.
• the measuring apparatus of the invention for measuring pipeline faults comprises on one side of the pipe a gamma radiation or x-ray source and on the other side, two detectors located at a distance of each other in the axial direction of the pipe and aligned with the radiation source, and an output device, the radiation source being disposed to direct measuring beams through the walls of the pipe that is being measured, at an angle relative to each other; the detectors being dis ⁇ posed to detect the beams that have traversed the pipe walls; and the output device being disposed to record a signal characterizing the pipe wall thickness.
• the measuring apparatus and measuring proce ⁇ dure of the invention are based on the fact that two collineated radiations which are moved one after the other pass through the pipe wall with a given spacing when entering the pipe, and when they come out through the mantle on the other side of the pipe their spacing is different, preferably greater. Therefore comparison of the results of measurement obtained from different beams enables inferences to be drawn as to on which side of the pipe and at what location is the measured point of- observation, such as e.g. a thinned-down area.
• the measuring apparatus and the procedure are based on the fact that the radiation which is being used is absorbed by the pipe mantle in greater propor ⁇ tion, the greater the thickness at the traversing point. It is therefore also possible with the apparatus and procedure of the invention to measure obstructions in the pipe, in addition to various instances of cor- rosion damage and the like.
• the pipes that are being measured may be made of reinforced plastic, steel, aluminium, copper, etc., and they may also be lagged with various lagging mate ⁇ rials.
• the radiation used in the invention is gamma or x-ray radiation.
• the wavelength of the radiation is on the order of 10-° cm (gamma radiation) and 10 _ ⁇ to 10- 6 cm ( x-rays) .
• Ca 137 is a particularly well suited radiation source for the measurement.
• the radiation that has passed through the pipe walls is detected with detectors on the opposite side of the pipe.
• detectors one may use any kind of con- ventional radiation detectors which are fit for detect ⁇ ing the gamma or x-ray radiation in question.
• the sig ⁇ nals from the detectors may be amplified, and the sig ⁇ nals may be output by conventional methods known in the art, with a plotter, on film, on magnetic tape, etc.
• the radiation from the radiation source is accurately aligned with a colli ator before and/or after the pipe that is being measured, so that sharp delimiting of the radiation is achieved.
• the angle enclosed by the radiation observed by the detectors and the nor- al on the pipe is within l to 60°, suitably 1 to 15 ° , advantageously 1 to 5°, the radiations being at equal and opposite angles relative to the normal.
• the conditions of measurement will be exactly equal for both radiations, and any differences observed in the radiations will signify existing deviations in the structure of the pipe or obstruction present in the pipe.
• the distance between detectors is advantage ⁇ ously on the order of 10 to 100 mm, suitably 10 to 60 mm, e.g. 10 to 20 mm.
• the beams going to the detectors may be at ⁇ tenuated with filtering plates, to be appropriate for the detectors.
• filtering plates may be inserted in the path either after the radiation source and before the pipe or after the pipe and before the detectors.
• the material to be used for the filtering plates is a conventional material used to attenuate radiation.
• the signals from the detectors may be elect ⁇ rically amplified to be appropriate for the plotter, each channel by itself, whereby the thickness can be read, once the apparatus has been calibrated.
• the measurement of the invention is carried out by moving the measuring apparatus and the pipe under measurement relative to each other. This may be done either by moving the measuring apparatus relative to the stationary pipe or by moving the pipe relative to the stationary measuring apparatus.
• the measurement of the invention is advantage ⁇ ously performed as a null balance measurement in that the radiations to be measured are continuously compared with each other and only when the radiation intensities differ, the magnitude of the difference and its loca ⁇ tion in the pipeline are recorded in any convenient manner.
• the advantage of the invention over prior art is that it affords a rapid, accurate and simple way of measurement without any interference with the operation of the pipelines.
• FIG. 1 presents a schematic diagram of an apparatus according to the invention
• Fig. 2 presents an arrangement according to the inven ⁇ tion
• Fig. 3 shows the example of Fig. 2, seen from another viewing angle
• Fig. 4 illustrates the radiation intensities measured by the detectors.
• a gamma or x-ray radia ⁇ tion source 2 and two detectors 3,3 s - have been placed on opposite sides of the walls of the pipe 1 to be measured.
• the detectors have been placed one after the other in the axial direction of the pipe to be measur ⁇ ed, and so aligned relative to each other that the beams striking the detectors form equal angles ⁇ with the normal on the pipe under observation.
• the radiation emitted by the radiation source 2 is collineated with the aid of collimators 5,5 1 ,5 2 ,5 3 before the pipe 1, and after the pipe, to form two sharp beams which are directed accurately into the detectors SjS 3 -.
• the radia ⁇ tion may be attenuated with filtering plates 7 in order to adjust the radiation from the radiation source 2 to be appropriate for the detectors 3,3 .
• the measuring apparatus of Fig. 1 is operated as follows.
• the measuring apparatus is moved in the axial direction of the pipe 1, the radiations from the radiation source 2 traversing both walls of the pipe. If the pipes are of uniform thickness and faultless, the signals going to the output device 4 are similar and the output device gives out no signals in a null balance measurement.
• the intensity of the radiation changes if there are faults or other changes in the pipe walls.
• a rise or descent in intensity i.e., increase or decrease of the radia ⁇ tion passing through the pipe, indicates the wall thickness of the pipe.
• the measuring range is linear in the measuring direction in the axial direction of the pipe.
• the measuring speed when the measuring apparatus is being moved, depends on the detectors, and it may be such that the measurement can even be made at a walking pace.
• the first sign of this fault is received from the first beam, which is absorbed in the pipe structure in a different manner at the fault from that experienced at a faultless point.
• the x axis representing the pipe length gives infor ⁇ mation as to the location of the fault in the pipe.
• a similar fault signal is obtained from the other beam, whereby it is seen from the spacing of the fault signals in the x direction, on which of the two pipe walls the fault is located.
• the radiation source 2 and the detectors S ⁇ 3 - have been mounted on a transport means 6 by the aid of which the apparatus can be moved relative to the pipe 1 in the axial direction of the pipe, when a measurement is in progress.
• a transport means 6 consisting of an arc which is 3/4 of the pipe's circumference and which is centrally braced against the pipe with three supporting legs carrying wheels 8.
• the arc carries, on opposite sides of the pipe, one radiation source and two detec- tors, one after the other in the axial direction of the pipe.
• the detectors are aligned to be at an angle e.g. about 3° against the normal on the pipe, and spaced at 10 to 20 mm.
• the radiation is directed through the apertures of collimators located before the pipe, accurately into the apertures of two collimators on the other side in conjunction with the detectors, and fur ⁇ ther into the detectors, one specific beam into each.
• the radiation is attenuated in case of need with fil ⁇ tering plates for ascertaining the wall thickness and good functioning of the detectors.
• the detector signals are electrically amplified by methods known in the art, when needed to suit the plotter, each channel separate ⁇ ly by itself, whereby the thickness will be readable once the apparatus has been calibrated.
• the measuring apparatus of the invention can be employed in measuring the faults of various kinds of pipelines, such as faults in the pipe walls, foreign objects present in the pipes, and clogged pipes.
• the faults in the pipe walls can also be measured without removing the lagging, making the measurement through the lagging.

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• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Toxicology (AREA)
• Analysing Materials By The Use Of Radiation (AREA)
• Length-Measuring Devices Using Wave Or Particle Radiation (AREA)

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• 1989
  • 1989-11-23 FI FI895615A patent/FI895615A/fi not_active Application Discontinuation
• 1990
  • 1990-11-22 DE DE69027538T patent/DE69027538T2/de not_active Expired - Fee Related
  • 1990-11-22 JP JP2515372A patent/JPH05501608A/ja active Pending
  • 1990-11-22 US US07/858,988 patent/US5268952A/en not_active Expired - Fee Related
  • 1990-11-22 EP EP90916751A patent/EP0500661B1/de not_active Expired - Lifetime
  • 1990-11-22 WO PCT/FI1990/000282 patent/WO1991008470A1/en active IP Right Grant

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